shag7265

I have a 12 jkur automatic with 4.10 gears that will have a 2.5 lift and 35's very soon. Can I stay at 4.10 or what should I regear to?

Owl

Auto, or manual?

Do you have a SuperChip Flashpaq (or similar)?

I've read on other threads that 4.10's are OK with a manual transmission. I know I did a gear change with my automatic from 4.10's to 5.13's and have been very happy. However, the re-programming (via SuperChips) helps even more.

shag7265

Can't believe I left that important piece of info out. It is an automatic trans.

shag7265

I do not have a programmer. I was looking at the pro cals.

Owl

I've read good reviews on the ProCal, but I'm not familiar with it.

With the Flashpaq, you enter the tire size / gear ratio / type of fuel / disable TPMS and all kinds of neat stuff. Then the thing programs your Jeep accordingly. Now, as a disclaimer: this works for my 2010 (and will down to 2007). I don't know if they are ready for the 2012 line or not. So, prowl around the forums, and see what you can find out.

I do recall quite a debate going on about 4.88's vs. 5.13's. Apparently the larger the ratio, the smaller the pinion. The happy mediums appeared to be the 4.88 (also because these were the largest gears for the JK that were U.S. made). I chose the 5.13 because most of the folks here were singing its praises. I'm happy, for what it's worth.

Good luck to you.

roadking54

From what I've read from others on the forum, with a 2012 and 4.10's you should be fine....however, it all depends on what 'fine' is to you and your needs. I ran a 3" lift and 35's on stock 3.73's with OD off for months and it was fine....and you've got more HP. A programmer will be key though to recalibrate.

matprovo

I have a 2012 JKURubi with 2.5" TF lift and 35" Nitto Trail Grapplers. I don't see a need to regear but you certainly should get the pro cal. Changes the shift points to account for the larger mass you are turning. I've done a few road trips and no problems. Still sucks the gas but what do expect.

FlameRedJK

I have a 2012 JKU Sport, I run 35" MTR with 3.21 gears. When I got my lift put on, EVO suggested I didn't regear, I'm glad they did. After using the AEV ProCal, feels just like my stock JKU. The new 3.6 and tranny handle larger tires amazingly!!

Black Forest JK

I agree. I have a 2012 Sahara and did not re-gear. I used the Pro Cal for the 35's and the only time I feel the auto transmission looking for a gear is going up a steep bridge on the highway at 75-80 mph. I am on Nitto Trail Grapplers and a 4"Pro-Comp lift. I have looked around to see if anyone has had better results with re-gearing, but so far, it doesn't seem to be a big issue.

shag7265

Awesome, thanks for the replys.